US2010-102500A1 discloses an example of an image reading apparatus. The image reading apparatus includes a document table and a document cover. The document table includes a first window, and image sensor elements configured to read an image on a document placed on the first window. The document cover is pivotally coupled to the document table, via a hinge mechanism. The document cover is configured to pivot between a closed position in which the first window is covered, and an open position in which the first window is revealed.
The hinge mechanism disclosed in US2010-102500A1 is a free stop hinge that enables the document cover to be held open and be maintained at any upwardly pivoted position (i.e., at any angle relative to the document table). The free stop hinge includes a base portion and a pivot portion. The base portion is supported by the document table. The pivot portion is fixed to the document cover. The pivot portion allows the document cover to be pivotable relative to the base portion. The base portion accommodates a compression coil spring therein. The compression coil spring exerts biasing force between the base portion and the pivot portion, thereby holding the document cover at the open position so as to not close due to its own weight. This configuration helps a user of the image reading apparatus to readily place a document on the first window of the document table or remove the document from the first window while the cover is held at the open position.